To validate model predictions and test critical hypotheses, CO2 trapping and leakage processes
must be studied at the pressures and long length scales operative in the context of geologic
sequestration. In a partnership between Princeton University and the Lawrence Berkeley
National Laboratory funded by the U.S. National Science Foundation, lead investigator Catherine
Peters and principal investigators Jean Prevost and George Scherer are planning for DUSEL CO2,
a facility for experimental study of geologic carbon sequestration. The proposed facility will be
part of DUSEL, the deep underground laboratory being built in the Homestake mine in South
Dakota (Figure 9). DUSEL will be a world-class facility with access to depths of more than 2225
meters (7,400 ft), and will provide capabilities for research in physics, geosciences, biology, and
engineering. At present, the facility is being designed and the portfolio of experiments is being
prioritized. Construction is expected to start in 2013.

The planned DUSEL CO2 facility will enable study of CO2 vertical migration and trapping
mechanisms on realistic length scales and enable an unprecedented level of experimental control
and monitoring capabilities. The existing matrix of shafts and drifts in the mine will be exploited
for construction of vertical half-kilometer column pressure vessels in which CO2 flow can be
observed. Instrumentation will enable detailed monitoring of flow, pressure, temperature, brine
composition, CO2 concentrations, phase changes, geomechanics, and microbial activity. Fill
materials will mimic sedimentary layering, as well as cements in plugged wells.

As part of the initial experiments, the researchers plan to simulate a leak in which CO2 changes
from a supercritical fluid to a subcritical gas during upflow over tens to hundreds of meters. They
will also test for possible acceleration in CO2 flow due to increasing buoyancy and examine the
interactions of CO2 with cap-rocks and well cements to determine whether CO2 will enlarge flow
pathways or cause self-sealing. Finally, the team will investigate the effects of anaerobic,
thermophilic bacteria on CO2 conversion to methane and carbonate. The findings from these
unique experiments will advance carbon management technology worldwide and help reduce
global greenhouse gas emissions.